Dear HR expert, I need advise/solution from you, One of my worker, her position production leader,, she already work for more than 10 years, and she's resigning, effectively today 14/05/20, and she sent the message through WhatsApp to her HOD. She resigning due to she don't agree with current instructions by our management as she don't feel any appreciatiaon from the company. She just sent a short message through WhatsApp. No letter and nothing. She already work for more than 10 years, so she need to tender one month resignation letter right ? If she fail to do, can we hold her salary in this situation ? I need advise on this. Tq